The union is aiming to pressure the online retailer by threatening delays in package deliveries during the critical holiday season.

Teamsters union says Amazon workers at seven warehouses plan to walk off the job Thursday morning in multiple states.

Bundled up and huddled around propane and diesel heaters, the group appeared upbeat and optimistic as strike organizers provided them with hats, jackets, hand warmers, beverages and snacks.

Amazon workers at four California facilities will join their striking colleagues on the picket line Thursday morning after reaching a stalemate during labor negotiations.

The Teamsters said the strike will begin Thursday at several facilities, including in New York City, Atlanta, California and Illinois.

Amazon workers have walked off the job at seven facilities throughout the U.S., including the company's Queens location in New York City, as they push for contract talks with their union.

The International Brotherhood of Teamsters said workers at seven Amazon facilities will begin a strike on Thursday morning.

Amazon Teamsters are launching what they call “the largest strike against Amazon in U.S. history,” including at the Johnston and Fall River sites. They say the nationwide strike started at 6 a.m. this morning. We’ll have more details on @NBC10 at noon. pic.twitter.com/J9bdeEcAfO

Teamsters requested an investigation of the flood from Amazon's warehouse that swamped a picket line in Queens; they also filed for a restraining order against the NYPD.

Lakeville police have spoken to the driver who left about 80 packages in the woods near Bedford Street in Middleboro. What going to happen now?

A spokesperson for Amazon said the union claims they represent “thousands of Amazon employees and drivers” when they don’t.